Organic light-emitting display apparatus and method of manufacturing the same

ABSTRACT

An organic light-emitting display apparatus includes a substrate; a pixel electrode over the substrate; a pixel-defining layer including an opening that exposes at least a portion of the pixel electrode; an intermediate layer, which is over the portion of the pixel electrode exposed by the opening and includes an organic emission layer; a counter electrode over the intermediate layer; and an encapsulating structure, which is over the counter electrode and includes at least one inorganic layer and at least one organic layer, and the at least one organic layer includes quantum dots and is in the opening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/203,735, filed on Jul. 6, 2016, which claims priority to and thebenefit of Korean Patent Application No. 10-2015-0187639, filed on Dec.28, 2015, in the Korean Intellectual Property Office, the disclosure ofeach of which is incorporated herein in its entirety by reference.

BACKGROUND 1. Field

Aspects of one or more embodiments relate to an organic light-emittingdisplay apparatus and a method of manufacturing the same, and moreparticularly, to an organic light-emitting display apparatus includingquantum dots and a method of manufacturing the same.

2. Description of the Related Art

An organic light-emitting display apparatus is a self-luminescentdisplay apparatus that includes a hole injection electrode, an electroninjection electrode, and an organic emission layer therebetween andemits light as excitons, which are generated as holes injected by thehole injection electrode and electrons injected by the electroninjection electrode combine in the organic emission layer, andtransition from an excited state to a ground state.

Since an organic light-emitting display apparatus, which is aself-luminescent display apparatus, does not require a separate lightsource, the organic light-emitting display apparatus may be driven witha low voltage and may be configured into a lightweight and slimapparatus. Furthermore, due to excellent properties including a viewingangle, contrast, and a response speed, an organic light-emitting displayapparatus is widely applied to portable apparatuses, such as an MP3player or a mobile phone, a television (TV), etc.

Recently, for reduced thickness and/or flexibility of an organiclight-emitting display apparatus, a thin-film encapsulation (TFE)including at least one inorganic layer and at least one organic layer isemployed to seal an organic light-emitting device.

SUMMARY

According to an aspect of one or more embodiments, an organiclight-emitting display apparatus has enhanced color purity that may beeasily manufactured as a flexible display apparatus.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to one or more embodiments, an organic light-emitting displayapparatus includes a substrate; a pixel electrode over the substrate; apixel-defining layer including an opening that exposes at least aportion of the pixel electrode; an intermediate layer, which is over theportion of the pixel electrode exposed by the opening and includes anorganic emission layer; a counter electrode over the intermediate layer;and an encapsulating structure, which is over the counter electrode andincludes at least one inorganic layer and at least one organic layer,and the at least one organic layer includes quantum dots and is in theopening.

The thickness of the at least one organic layer including the quantumdots may be less than or equal to about 20 μm.

According to an embodiment, the at least one inorganic layer may have athickness less than or equal to about 5 μm and may include at least oneof silicon nitride (SiN_(x)), silicon oxide (SiO₂), silicon oxynitride(SiO_(x)N_(y)) or aluminum oxide (Al₂O₃).

According to an embodiment, the pixel electrode may be a reflectiveelectrode that reflects light, and the counter electrode may be atransparent or semi-transparent electrode that at least partiallytransmits light therethrough.

According to an embodiment, the organic emission layer may emit bluelight.

According to an embodiment, the quantum dots may absorb at least a partof the blue light and emit yellow light, and at least a part of the bluelight may be transmitted through the organic layer including the quantumdots.

According to an embodiment, the at least one inorganic layer may includea first inorganic layer over the counter electrode and a secondinorganic layer over the first inorganic layer, and the at least oneorganic layer including the quantum dots may include a lower organiclayer between the first inorganic layer and the second inorganic layer.

According to an embodiment, the second inorganic layer may include afirst area directly contacting the first inorganic layer, and a secondarea that is spaced apart from the first inorganic layer by the lowerorganic layer.

According to an embodiment, the at least one organic layer including thequantum dots may further include an upper organic layer over the secondinorganic layer, and the at least one inorganic layer may furtherinclude a third inorganic layer over the upper organic layer.

According to an embodiment, the pixel electrode may include a firstpixel electrode, a second pixel electrode, and a third pixel electrodethat are apart from one another, the pixel-defining layer may include afirst opening, a second opening, and a third opening that expose atleast portions of the first pixel electrode, the second pixel electrode,and the third pixel electrode, respectively, and the intermediate layermay include a first intermediate layer over the first pixel electrode, asecond intermediate layer over the second pixel electrode, and a thirdintermediate layer over the third pixel electrode.

According to an embodiment, the at least one organic layer including thequantum dots may include a first organic layer that is in the firstopening and includes first quantum dots of the quantum dots, a secondorganic layer that is in the second opening and includes second quantumdots of the quantum dots, and a third organic layer that is in the thirdopening and includes third quantum dots of the quantum dots.

According to an embodiment, the first intermediate layer, the secondintermediate layer, and the third intermediate layer may emit red light,green light, and blue light, respectively, and the first quantum dots,the second quantum dots, and the third quantum dots may be red quantumdots, green quantum dots, and blue quantum dots, respectively.

According to an embodiment, all of the first intermediate layer, thesecond intermediate layer, and the third intermediate layer may emitwhite light, and the first quantum dots, the second quantum dots, andthe third quantum dots may be red quantum dots, green quantum dots, andblue quantum dots, respectively.

According to an embodiment, the first organic layer, the second organiclayer, and the third organic layer may be separated from one another bythe pixel-defining layer.

According to one or more embodiments, a method of manufacturing anorganic light-emitting display apparatus includes forming a pixelelectrode disposed over a substrate; forming a pixel-defining layerincluding an opening that exposes at least a portion of the pixelelectrode over the pixel electrode; forming an intermediate layer, whichincludes an organic emission layer, over the portion of the pixelelectrode exposed by the opening; forming a counter electrode over theintermediate layer; and forming an encapsulating structure, whichincludes at least one inorganic layer and at least one organic layerover the counter electrode, wherein the organic layer includes quantumdots and is in the opening.

According to an embodiment, the thickness of the at least one organiclayer including the quantum dots may be less than or equal to about 20μm.

According to an embodiment, the at least one inorganic layer may have athickness less than or equal to about 5 μm and may include at least oneof silicon nitride (SiN_(x)), silicon oxide (SiO₂), silicon oxynitride(SiO_(x)N_(y)), and aluminum oxide (Al₂O₃).

According to an embodiment, the forming of the encapsulating structuremay include forming a first inorganic layer of the at least oneinorganic layer over the counter electrode; forming an organic layer ofthe at least one organic layer including the quantum dots over the firstinorganic layer; and forming a second inorganic layer of the at leastone inorganic layer over the organic layer.

According to an embodiment, the forming of the organic layer may includeforming an organic material having dispersed therein the quantum dots inthe opening included in the pixel-defining layer via inkjet-printing;and curing the organic material having dispersed therein the quantumdots.

According to an embodiment, the forming of the second inorganic layermay include forming the second inorganic layer to include a first areadirectly contacting the first inorganic layer, and a second area that isspaced apart from the first inorganic layer by the organic layerincluding the quantum dots.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic sectional view of an organic light-emittingdisplay apparatus according to an embodiment;

FIG. 2 is a schematic sectional view of an organic light-emittingdisplay apparatus according to another embodiment;

FIGS. 3A through 3G are sectional diagrams showing a method ofmanufacturing the organic light-emitting display apparatus of FIG. 2,according to an embodiment; and

FIG. 4 is a schematic sectional view of an organic light-emittingdisplay apparatus according to another embodiment.

DETAILED DESCRIPTION

As the inventive concept allows for various changes and numerousembodiments, some particular embodiments will be illustrated in thedrawings and described in further detail in the following description.However, this is not intended to limit the inventive concept toparticular modes of practice, and it is to be appreciated that allchanges, equivalents, and substitutes that do not depart from the spiritand technical scope of the inventive concept are encompassed in theinventive concept. In the description of the inventive concept, certaindetailed explanations of the related art are omitted when it is deemedthat they may unnecessarily obscure the essence of the inventiveconcept.

It will be understood that although the terms “first,” “second,” etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

It will be understood that when a layer, region, or component isreferred to as being “formed on” another layer, region, or component, itcan be directly or indirectly formed on the other layer, region, orcomponent. That is, for example, intervening layers, regions, orcomponents may be present.

Sizes of elements in the drawings may be exaggerated for convenience ofexplanation. In other words, since sizes and thicknesses of componentsin the drawings may be arbitrarily illustrated for convenience ofexplanation, the following embodiments are not limited thereto.

Reference will now be made in further detail to some embodiments,examples of which are illustrated in the accompanying drawings, whereinlike reference numerals refer to like elements throughout. In thisregard, the present embodiments may have different forms and should notbe construed as being limited to the descriptions set forth herein.Accordingly, the embodiments are merely described below, by referring tothe figures, to explain aspects of the present description. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items. Expressions such as “at least oneof” when preceding a list of elements, modify the entire list ofelements, and do not modify the individual elements of the list.

FIG. 1 is a schematic sectional view of an organic light-emittingdisplay apparatus 1 according to an embodiment.

Referring to FIG. 1, the organic light-emitting display apparatus 1according to an embodiment includes a flexible substrate 110, a pixelelectrode 120 disposed over the flexible substrate 110, an intermediatelayer 130, which is disposed over the pixel electrode 120 and includesan organic emission layer 133, a counter electrode 140 disposed over theintermediate layer 130, and an encapsulating structure 150, which isdisposed over the counter electrode 140 and includes at least oneinorganic layer 151, 153, 155 and at least one organic layer 152, 154including quantum dots 152 a and 154 a.

The flexible substrate 110 may include various materials, such as glass,a metal, or plastic. Here, the flexible substrate 110 may refer to asubstrate that may be easily bent, curved, folded, or rolled. Theflexible substrate 110 may include ultra-thin glass, a metal, orplastic. For example, if the flexible substrate 110 includes plastic,the flexible substrate 110 may include polyimide (PI), but is notlimited thereto.

An organic light-emitting device OLED is disposed over the flexiblesubstrate 110, where the organic light-emitting device OLED may includethe pixel electrode 120, the intermediate layer 130, and the counterelectrode 140.

The pixel electrode 120 may be a reflective electrode including areflective layer. According to an embodiment, the reflective layer mayinclude at least one of silver (Ag), magnesium (Mg), aluminum (Al),platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd),iridium (Ir), and chromium (Cr), where a transparent or semi-transparentelectrode layer including at least one selected from a group consistingof indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO),indium oxide (In₂O₃), indium gallium oxide (IGO), and aluminum zincoxide (AZO) may be further disposed over the reflective layer. Forexample, the pixel electrode 120 may include three layers of ITO/Ag/ITO.

The counter electrode 140 may include various conductive materials andmay be a transparent or semi-transparent electrode. According to anembodiment, the counter electrode 140 may include one or more materialsselected from among silver (Ag), aluminum (Al), ytterbium (Yb), titanium(Ti), magnesium (Mg), nickel (Ni), lithium (Li), calcium (Ca), copper(Cu), LiF/Ga, LiF/Al, MgAg, and CaAg, where the counter electrode 140may include a thin film having a thickness from several nm to dozens ofnm by using one or more of the above-stated materials to transmit lighttherethrough.

The organic light-emitting display apparatus 1 according to anembodiment may be a top-emission type display apparatus in which lightis emitted from the intermediate layer 130 toward the encapsulatingstructure 150.

The intermediate layer 130 includes the organic emission layer 133 andmay further include a common layer. According to an embodiment, thecommon layer may include a hole injection layer 131 and a hole transportlayer 132 between the pixel electrode 120 and the organic emission layer133 and may include an electron transport layer 134 and an electroninjection layer 135 between the organic emission layer 133 and thecounter electrode 140.

However, the inventive concept is not limited thereto. The intermediatelayer 130 may not include at least some of the above-stated commonlayers or may further include function layers other than theabove-stated common layers.

According to an embodiment, the organic light-emitting device OLED mayemit red light, green light, or blue light according to the type of theorganic emission layer 133. However, the inventive concept is notlimited thereto, and the organic light-emitting device OLED may emitother light colors or white light.

In the case the organic light-emitting device OLED emits white light,the organic emission layer 133 included in the organic light-emittingdevice OLED may have a structure in which different types of organicemission layers are stacked or may be a layer including a combination ofdifferent organic materials.

The encapsulating structure 150 may be disposed over the organiclight-emitting device OLED, where the encapsulating structure 150 mayinclude at least one inorganic layer 151, 153, 155 and at least oneorganic layer 152, 154. According to an embodiment, the encapsulatingstructure 150 may include a first inorganic layer 151 disposed over thecounter electrode 140, a lower organic layer 152, which is disposed overthe first inorganic layer 151 and includes quantum dots 152 a, and asecond inorganic layer 153 disposed over the lower organic layer 152. Inother words, the lower organic layer 152 may be between the firstinorganic layer 151 and the second inorganic layer 153. An upper organiclayer 154 including quantum dots 154 a may be disposed over the secondinorganic layer 153, and a third inorganic layer 155 may be furtherdisposed over the upper organic layer 154.

Although FIG. 1 shows a case in which the three inorganic layers 151,153, and 155 and the two organic layers 152 and 154 are disposed, theinventive concept is not limited thereto.

The encapsulating structure 150 seals the organic light-emitting deviceOLED to prevent or substantially prevent the organic light-emittingdevice OLED from being exposed to the outside atmosphere or impurities.Since the encapsulating structure 150 has a very small thickness, theencapsulating structure 150 may be used as an encapsulating structure ina bendable or foldable flexible display apparatus.

A function layer 170 that enhances characteristics emitted by theorganic light-emitting device OLED may be further disposed between thecounter electrode 140 and the encapsulating structure 150, where thefunction layer 170 may include a capping layer and a cover layer thatprotects the organic light-emitting device OLED from possible damageduring an operation using plasma, for example. According to anembodiment, the capping layer may include an organic material, whereasthe cover layer may include LiF.

According to an embodiment, the inorganic layers 151, 153, and 155 mayinclude silicon nitride (SiN_(x)), silicon oxide (SiO₂), siliconoxynitride (SiO_(x)N_(y)) or aluminum oxide (Al₂O₃) and may block orreduce permeation of impurities, such as moisture or oxygen, to theorganic light-emitting device OLED.

The organic layers 152 and 154 may include organic materials 152 b and154 b and the quantum dots 152 a and 154 a that are respectivelydispersed in the organic materials 152 b and 154 b. The organic layers152 and 154 may be used together with the inorganic layers 151, 153, and155 to improve sealing characteristics of the encapsulating structure150 and to planarize rough surfaces therebelow. The organic materials152 b and 154 b may include various organic materials, such asepoxy-based resins, acryl-based resins, or polyimide-based resins, andmay be inkjet-printable materials.

According to an embodiment, a thickness t1 of each of the inorganiclayers 151, 153, and 155 may be less than or equal to about 5 μm,whereas a thickness t2 of each of the organic layers 152 and 154 may beless than or equal to about 20 μm. If the thickness t1 of each of theinorganic layers 151, 153, and 155 exceeds about 5 μm or the thicknesst2 of each of the organic layers 152 and 154 exceeds about 20 μm, it maybe difficult to reduce the thickness of the organic light-emittingdisplay apparatus 1 and/or to manufacture the organic light-emittingdisplay apparatus 1 as a flexible display apparatus.

Furthermore, the thickness t1 of each of the inorganic layers 151, 153,and 155 may be greater than about 300 nm, whereas the thickness t2 ofeach of the organic layers 152 and 154 may be greater than about 1 μm.If the thickness t1 of each of the inorganic layers 151, 153, and 155 isless than or equal to about 300 nm, it may be difficult to blockpermeation of moisture or oxygen to the organic light-emitting deviceOLED. If the thickness t2 of each of the organic layers 152 and 154 isless than or equal to about 1 μm, it may be difficult to uniformlydisperse the quantum dots 152 a and 154 a having sizes from several nmto hundreds of nm.

The quantum dots 152 a and 154 a are respectively dispersed in theorganic materials 152 b and 154 b. A quantum dot refers to a sphericalsemiconductor nano-material having a size from several nm to hundreds ofnm and may include a core CR including a material having a small bandgap and a shell SL that surrounds the core CR. Unlike a material in abulk state, a quantum dot has discontinuous band gap energy due to thequantum confinement effect. Therefore, a quantum dot may absorb light ofa certain wavelength and emit light of a wavelength longer than that ofthe absorbed light, where the emitted light may have very high colorpurity with a small full width at half maximum (FWHM). The quantum dotmay further include a capping ligand CL for preventing quantum dots frombeing massed with one another and improving solubility.

According to an embodiment, the core CR may include a group II-VIsemiconductor, a group III-V semiconductor, a group I-III-VIsemiconductor, or a group VI-IV semiconductor and may include one ofCdSe, CdTe, CdS, ZnSe, ZnO, ZnTe, InP, InAs, GaP, GaInP₂, PbS, TiO, Agl,AgBr, PbSe, In₂S₃, In₂Se₃, Cd₃P₂, Cd₃As₂, InGaN, and InN.

Intervals between energy bands vary depending on sizes of the quantumdots. Therefore, if same quantum dots with different sizes are used,light of different wavelengths may be emitted. An energy band gap of aquantum dot increases as the size of the quantum dot decreases, and thusthe wavelength of light emitted thereby decreases.

The quantum dots 152 a and 154 a included in the organic layers 152 and154 may absorb light of a certain wavelength and emit light of awavelength longer than that of the absorbed light. According to anembodiment, the quantum dots 152 a and 154 a may be red quantum dotsthat emit red light, green quantum dots that emit green light, bluequantum dots that emit blue light, or yellow quantum dots that emityellow light.

According to an embodiment, the organic light-emitting device OLED mayemit blue light, and the quantum dots 152 a and 154 a included in theorganic layers 152 and 154 of the encapsulating structure 150 may beyellow quantum dots that absorb blue light and emit yellow light.According to another embodiment, the quantum dots 152 a and 154 a may bea combination of red quantum dots that absorb blue light and emit redlight and green quantum dots that emit green light. In this case, yellowlight may be emitted as a combination of red light and green light.

According to another embodiment, the quantum dots 152 a included in thesingle organic layer 152 may be red quantum dots, whereas the quantumdots 154 a included in the other organic layer 154 may be green quantumdots.

A part of blue light emitted by the organic light-emitting device OLEDmay not be absorbed by the encapsulating structure 150 and may betransmitted therethrough, whereas the other part of the blue light maybe absorbed by the quantum dots 152 a and 154 a included in theencapsulating structure 150 and transformed to yellow light. As aresult, the organic light-emitting display apparatus 1 may emit whitelight as a combination of the blue light and the yellow light.

FIG. 2 is a schematic sectional view of an organic light-emittingdisplay apparatus 2 according to another embodiment. Descriptions belowof the organic light-emitting display apparatus 2 according to anotherembodiment will focus on differences between the organic light-emittingdisplay apparatus 2 of FIG. 2 and the organic light-emitting displayapparatus 1 previously described.

Referring to FIG. 2, the organic light-emitting display apparatus 2according to an embodiment may include a substrate 210, a pixelelectrode 220 disposed over the substrate 210, a pixel-defining layer260 including an opening 260 h that exposes at least a portion of thepixel electrode 220, an intermediate layer 230, which is disposed on theportion of pixel electrode 220 exposed by the opening 260 h and includesan organic emission layer, a counter electrode 240 disposed over theintermediate layer 230, and an encapsulating structure 250, which isdisposed over the counter electrode 240 and includes at least oneinorganic layer 251 or 253 and at least one organic layer 252 includingquantum dots 252 a.

A pixel circuit that drives an organic light-emitting device OLED andincludes at least one thin-film transistor (TFT) may be between thesubstrate 210 and the organic light-emitting device OLED.

The TFT may include an active layer 213 disposed over the substrate 210,a gate electrode 215 disposed over at least a portion of the activelayer 213, and a source electrode 217S and a drain electrode 217D thatare disposed over the gate electrode 215 and are electrically connectedto the active layer 213.

A buffer layer 212 may be between the substrate 210 and the active layer213, a first insulation layer 214 may be between the active layer 213and the gate electrode 215, and a second insulation layer 216 may bedisposed over the gate electrode 215.

A third insulation layer 218 may be disposed over the second insulationlayer 216 and covers the source electrode 217S and the drain electrode217D, and the third insulation layer 218 may include a via hole VIA thatexposes at least a portion of the drain electrode 217D. The TFT may beelectrically connected to the pixel electrode 220 via the via hole VIA.

According to an embodiment, the pixel electrode 220 may be a reflectiveelectrode, the counter electrode 240 may be a transparent orsemi-transparent electrode, and light emitted by the organic emissionlayer included in the intermediate layer 230 may be transmitted throughthe counter electrode 240 and emitted from the organic light-emittingdisplay apparatus 2. In other words, the organic light-emitting displayapparatus 2 may be a top-emission type display apparatus.

According to an embodiment, the TFT may overlap the pixel electrode 220in a plan view. In other words, when viewed in a direction perpendicularto the main surfaces of the substrate 210, the pixel electrode 220 andthe TFT may at least partially overlap each other.

In the top-emission type organic light-emitting display apparatus 2,since at least a portion of the pixel circuit is between the substrate210 and the pixel electrode 220, it is not necessary to secure aseparate space for arranging the pixel circuit, and thus an apertureratio of the organic light-emitting display apparatus 2 may beincreased.

The intermediate layer 230 includes an organic emission layer and mayfurther include a hole injection layer, a hole transport layer, anelectron transport layer, and/or an electron injection layer. Accordingto an embodiment, the intermediate layer 230 includes an organicemission layer, and the organic light-emitting device OLED may emit redlight, green light, or blue light according to the type of the organicemission layer. However, the inventive concept is not limited thereto,and the organic light-emitting device OLED may emit other light colorsor white light.

The encapsulating structure 250 may be disposed over the organiclight-emitting device OLED, where the encapsulating structure 250 mayinclude at least one inorganic layer 251, 253 and at least one organiclayer 252. According to an embodiment, the encapsulating structure 250may include a first inorganic layer 251 disposed over the counterelectrode 240, a lower organic layer 252, which is disposed over thefirst inorganic layer 251 and includes quantum dots 252 a, and a secondinorganic layer 253 disposed over the lower organic layer 252. AlthoughFIG. 2 shows a case in which two inorganic layers 251 and 253 and onelower organic layer 252 are disposed, the inventive concept is notlimited thereto.

According to an embodiment, the inorganic layers 251 and 253 may includesilicon nitride (SiN_(x)), silicon oxide (SiO₂), silicon oxynitride(SiO_(x)N_(y)) or aluminum oxide (Al₂O₃) and may block or reducepermeation of impurities, such as moisture or oxygen, to the organiclight-emitting device OLED.

The lower organic layer 252 may include an organic material 252 b andthe quantum dots 252 a that are dispersed in the organic material 252 b.The lower organic layer 252 may be used together with the inorganiclayers 251 and 253 to improve sealing characteristics of theencapsulating structure 250 and to planarize rough surfaces therebelow.The organic material 252 b may include various organic materials, suchas epoxy-based resins, acryl-based resins, or polyimide-based resins,and may be an inkjet-printable material.

According to an embodiment, a thickness t1 of each of the inorganiclayers 251 and 253 may be less than or equal to about 5 μm, whereas athickness t2 of the lower organic layer 252 may be less than or equal toabout 20 μm. If the thickness t1 of each of the inorganic layers 251 and253 exceeds about 5 μm or the thickness t2 of the lower organic layer252 exceeds about 20 μm, it may be difficult to reduce the thickness ofthe organic light-emitting display apparatus 2 and/or to manufacture theorganic light-emitting display apparatus 2 as a flexible displayapparatus.

Furthermore, the thickness t1 of each of the inorganic layers 251 and253 may be greater than about 300 nm, whereas the thickness t2 of thelower organic layer 252 may be greater than about 1 μm. If the thicknesst1 of each of the inorganic layers 251 and 253 is less than or equal toabout 300 nm, it may be difficult to block permeation of moisture oroxygen to the organic light-emitting device OLED. If the thickness t2 ofthe lower organic layer 252 is less than or equal to about 1 μm, it maybe difficult to uniformly disperse the quantum dots 252 a having sizesfrom several nm to hundreds of nm.

The lower organic layer 252 including the quantum dots 252 a may beinside the opening 260 h in the pixel-defining layer 260. In otherwords, the lower organic layer 252 may be in an area defined by thepixel-defining layer 260.

Therefore, according to an embodiment, the lower organic layer 252 maybe only in an area corresponding to the opening 260 h, between the firstinorganic layer 251 and the second inorganic layer 253. The secondinorganic layer 253 may include a first area 253 a that directlycontacts the first inorganic layer 251 and a second area 253 b that isdisposed or spaced apart from the first inorganic layer 251 by the lowerorganic layer 252.

The first area 253 a may correspond to an area in which thepixel-defining layer 260 is disposed, whereas the second area 253 b maycorrespond to an area above the pixel electrode 220 exposed by theopening 260 h in the pixel-defining layer 260.

The quantum dots 252 a included in the lower organic layer 252 mayabsorb light of a certain wavelength and emit light of a wavelengthlonger than that of the absorbed light. According to an embodiment, thequantum dots 252 a may be red quantum dots that emit red light, greenquantum dots that emit green light, blue quantum dots that emit bluelight, or yellow quantum dots that emit yellow light.

According to an embodiment, the organic light-emitting device OLED mayemit blue light, and the quantum dots 252 a included in the lowerorganic layer 252 of the encapsulating structure 250 may be yellowquantum dots that absorb blue light and emit yellow light or acombination of red quantum dots that absorb blue light and emit redlight and green quantum dots that emit green light.

A part of blue light emitted by the organic light-emitting device OLEDmay not be absorbed by the encapsulating structure 250 and may betransmitted therethrough, whereas the other part of the blue light maybe absorbed by the quantum dots 252 a included in the encapsulatingstructure 250 and transformed to yellow light. As a result, the organiclight-emitting display apparatus 2 may emit white light as a combinationof the blue light and the yellow light.

However, the inventive concept is not limited thereto. The organiclight-emitting device OLED included in the organic light-emittingdisplay apparatus 2 may emit light of various colors, and the organiclight-emitting display apparatus 2 including the organic light-emittingdevice OLED and the encapsulating structure 250 may emit light ofvarious colors other than white light, such as red light, green light,blue light, and yellow light.

FIGS. 3A through 3G are sectional diagrams showing (e.g., sequentiallyshowing) a method of manufacturing the organic light-emitting displayapparatus 2 of FIG. 2, according to an embodiment.

A method of manufacturing an organic light-emitting display apparatusaccording to an embodiment includes formation of the pixel electrode 220over the substrate 210, formation of the pixel-defining layer 260, whichincludes the opening 260 h exposing at least a portion of the pixelelectrode 220, over the pixel electrode 220, formation of theintermediate layer 230 including the organic emission layer over theportion of the pixel electrode 220 exposed by the opening 260 h,formation of the counter electrode 240 over the intermediate layer 230,and formation of the encapsulating structure 250, which includes the atleast one inorganic layer 251, 253 and the at least one organic layer252 including the quantum dots 252 a and disposed inside the opening 260h, over the counter electrode 240.

Referring to FIG. 3A, after the pixel circuit including a switchingdevice, such as the TFT, is formed over the substrate 210, the pixelelectrode 220 electrically connected to the pixel circuit is formed.

The pixel electrode 220 may be a reflective electrode including areflective layer. According to an embodiment, the reflective layer mayinclude at least one selected from silver (Ag), magnesium (Mg), aluminum(Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium(Nd), iridium (Ir), and chromium (Cr), where a transparent orsemi-transparent electrode layer including at least one selected from agroup consisting of indium tin oxide (ITO), indium zinc oxide (IZO),zinc oxide (ZnO), indium oxide (In₂O₃), indium gallium oxide (IGO), andaluminum zinc oxide (AZO) may be further disposed over the reflectivelayer. For example, the pixel electrode 220 may include three layers ofITO/Ag/ITO.

The pixel electrode 220 may be formed as an island-like structure byforming the metal and the conductive oxide over the substrate 210 andpatterning the same.

Referring to FIG. 3B, the pixel-defining layer 260 including the opening260 h that exposes at least a portion of the pixel electrode 220 may beformed over the pixel electrode 220.

The pixel-defining layer 260 may include an organic material, such aspolyimide (PI), where the pixel-defining layer 260 including the opening260 h that exposes a portion of the pixel electrode 220 may be formed byforming an organic material over the substrate 210 to cover the pixelelectrode 220 and patterning the same.

The portion exposed by the opening 260 h may be the center area of thepixel electrode 220, whereas the portion covered by the pixel-defininglayer 260 may be the edge area of the pixel electrode 220.

Referring to FIG. 3C, the intermediate layer 230 including the organicemission layer may be formed over the portion of the pixel electrode 220exposed by the opening 260 h in the pixel-defining layer 260. Theintermediate layer 230 includes the organic emission layer and mayfurther include at least one of a hole injection layer (HIL), a holetransport layer (HTL), an electron transport layer (ETL), and anelectron injection layer (EIL). Although not shown, the HIL, the HTL,the ETL, and the EIL may not only be disposed inside the opening 260 h,but also extend onto the top of the pixel-defining layer 260.

The organic emission layer may emit red light, green light, blue light,or white light.

Referring to FIG. 3D, the counter electrode 240 may be formed over theintermediate layer 230. The counter electrode 240 may be disposed overthe intermediate layer 230 and the pixel-defining layer 260. The counterelectrode 240 may be a transparent or semi-transparent electrode.According to an embodiment, the counter electrode 240 may include one ormore materials selected from among silver (Ag), aluminum (Al), ytterbium(Yb), titanium (Ti), magnesium (Mg), nickel (Ni), lithium (Li), calcium(Ca), copper (Cu), LiF/Ga, LiF/Al, MgAg, and CaAg, where the counterelectrode 240 may include a thin film having a thickness from several nmto dozens of nm by using one or more of the above-stated materials totransmit light therethrough.

Referring to FIG. 3E, the first inorganic layer 251 may be formed overthe counter electrode 240. The first inorganic layer 251 may includesilicon nitride (SiN_(x)), silicon oxide (SiO₂), silicon oxynitride(SiO_(x)N_(y)) or aluminum oxide (Al₂O₃) and may be formed by using asputtering method or a chemical vapor deposition (CVD) method, forexample.

The thickness t1 of the first inorganic layer 251 may be less than orequal to about 5 μm.

Referring to FIG. 3F, the organic material 252 b having dispersedtherein the quantum dots 252 a may be formed inside the opening 260 h ofthe pixel-defining layer 260 over the first inorganic layer 251 viainkjet-printing, for example. The organic material 252 b may include anyof various organic materials, such as epoxy-based resins, acryl-basedresins, or polyimide-based resins.

By ejecting the organic material 252 b having dispersed therein thequantum dots 252 a from a nozzle 10 included in an inkjet printingapparatus, the organic material 252 b may be dropped into an areadefined by the pixel-defining layer 260 that functions as a barrier.

Referring to FIG. 3G, the lower organic layer 252 including the quantumdots 252 a may be formed by coating the organic material 252 b havingdispersed therein the quantum dots 252 a over the top surface of theportion of the first inorganic layer 251 inside the opening 260 h andcuring the same. The thickness t2 of the lower organic layer 252 may beless than or equal to about 20 μm.

Referring back to FIG. 2, by forming the second inorganic layer 253 overthe lower organic layer 252, the encapsulating structure 250 includingthe first inorganic layer 251, the lower organic layer 252, and thesecond inorganic layer 253 may be formed. The second inorganic layer 253may include the first area 253 a that directly contacts the firstinorganic layer 251 and the second area 253 b that is disposed or spacedapart from the first inorganic layer 251 by the lower organic layer 252.

Although not shown, a function layer that enhances characteristicsemitted by the organic light-emitting device OLED may be further formedbefore the first inorganic layer 251 is formed.

According to the organic light-emitting display apparatus 2 and themethod of manufacturing the same as described above, the organic layer252 including the quantum dots 252 a may be simply formed inside theopening 260 h in the pixel-defining layer 260 to enhance color purity ofthe organic light-emitting display apparatus 2, and the lower organiclayer 252, which is a part of the encapsulating structure 250, mayprevent or substantially prevent permeation of moisture or oxygen to theorganic light-emitting device OLED, together with the inorganic layers251 and 253.

Color purity of the organic light-emitting display apparatus 2 may beenhanced by introducing the quantum dots 252 a to the encapsulatingstructure 250 without adding a separate layer, and thus the organiclight-emitting display apparatus 2 may be easily manufactured as aflexible display apparatus.

FIG. 4 is a schematic sectional view of an organic light-emittingdisplay apparatus 3 according to another embodiment. Descriptions belowof the organic light-emitting display apparatus 3 according to anotherembodiment will focus on differences between the organic light-emittingdisplay apparatus 3 of FIG. 4 and the organic light-emitting displayapparatuses 1 and 2 previously described.

Referring to FIG. 4, the organic light-emitting display apparatus 3according to another embodiment may include a substrate 310, pixelelectrodes 320 r, 320 g, and 320 b disposed over the substrate 310, apixel-defining layer 360 including openings 360 hr, 360 hg, and 360 hbthat respectively expose at least portions of the pixel electrodes 320r, 320 g, and 320 b, intermediate layers 330 r, 330 g, and 330 b thatare disposed over respective portions of the pixel electrodes 320 r, 320g, and 320 b exposed by the openings 360 hr, 360 hg, and 360 hb andinclude organic emission layers, a counter electrode 340 disposed overthe intermediate layers 330 r, 330 g, and 330 b, and an encapsulatingstructure 350 including at least one inorganic layer 351, 353 and atleast one organic layer 352 r, 352 g, 352 b, where the organic layers352 r, 352 g, and 352 b include quantum dots 352 ra, 352 ga, and 352 baand are disposed in the openings 360 hr, 360 hg, and 360 hb,respectively.

The organic light-emitting display apparatus 3 according to anembodiment may include a plurality of pixels adjacent to one another,where the plurality of pixels may emit light of different colors. Eachof the plurality of pixels may include the pixel electrodes 320 r, 320g, and 320 b and the intermediate layers 330 r, 330 g, and 330 b.

The pixel electrodes 320 r, 320 g, and 320 b may include a first pixelelectrode 320 r, a second pixel electrode 320 g, and a third pixelelectrode 320 b that are apart from one another, and the pixel-defininglayer 360 may include a first opening 360 hr, a second opening 360 hg,and a third opening 360 hb that expose the first pixel electrode 320 r,the second pixel electrode 320 g, and the third pixel electrode 320 b,respectively.

The intermediate layers 330 r, 330 g, and 330 b may include a firstintermediate layer 330 r disposed over the first pixel electrode 320 r,a second intermediate layer 330 g disposed over the second pixelelectrode 320 g, and a third intermediate layer 330 b disposed over thethird pixel electrode 320 b. The counter electrode 340 may be disposedover the intermediate layers 330 r, 330 g, and 330 b.

A pixel circuit that drives the plurality of pixels may be between thesubstrate 310 and the pixel electrodes 320 r, 320 g, and 320 b. Thepixel circuit may include a first thin-film transistor TFTr, a secondthin-film transistor TFTg, and a third thin-film transistor TFTb thatare electrically connected to the first pixel electrode 320 r, thesecond pixel electrode 320 g, and the third pixel electrode 320 b,respectively. Each of the plurality of pixels may be turned on or off bythe pixel circuit.

According to an embodiment, the pixel electrodes 320 r, 320 g, and 320 bmay be reflective electrodes, the counter electrode 340 may be atransparent or semi-transparent electrode, and light emitted by organicemission layers included in the intermediate layers 330 r, 330 g, and330 b may be transmitted through the counter electrode 340 and emittedfrom the organic light-emitting display apparatus 3. In other words, theorganic light-emitting display apparatus 3 may be a top-emission typedisplay apparatus.

Each of the intermediate layers 330 r, 330 g, and 330 b includes anorganic emission layer and may further include a hole injection layer, ahole transport layer, an electron transport layer, and/or an electroninjection layer. The first intermediate layer 330 r, the secondintermediate layer 330 g, and the third intermediate layer 330 b mayinclude a first organic emission layer, a second organic emission layer,and a third organic emission layer, respectively, where a hole injectionlayer, a hole transport layer, an electron transport layer, and/or anelectron injection layer may be included in each of the firstintermediate layer 330 r, the second intermediate layer 330 g, and thethird intermediate layer 330 b.

According to an embodiment, the first intermediate layer 330 r, thesecond intermediate layer 330 g, and the third intermediate layer 330 bmay emit red light, green light, and blue light, respectively. Accordingto another embodiment, all of the first intermediate layer 330 r, thesecond intermediate layer 330 g, and the third intermediate layer 330 bmay emit white light. If all of the first intermediate layer 330 r, thesecond intermediate layer 330 g, and the third intermediate layer 330 bemit white light, the first intermediate layer 330 r, the secondintermediate layer 330 g, and the third intermediate layer 330 b mayhave a same structure in which different types of organic emissionlayers are stacked or may include layers including a combination ofdifferent organic materials.

The encapsulating structure 350 may be disposed over the counterelectrode 340, where the encapsulating structure 350 may include the atleast one inorganic layer 351, 353 and the at least one organic layer352 r, 352 g, 352 b. According to an embodiment, the encapsulatingstructure 350 may include a first inorganic layer 351 disposed over thecounter electrode 340, the organic layers 352 r, 352 g, and 352 b, whichare disposed over the first inorganic layer 351 and respectivelyincludes the quantum dots 352 ra, 352 ga, and 352 ba, and a secondinorganic layer 353 disposed over the organic layers 352 r, 352 g, and352 b.

According to an embodiment, the inorganic layers 351 and 353 may includesilicon nitride (SiN_(x)), silicon oxide (SiO₂), silicon oxynitride(SiO_(x)N_(y)) or aluminum oxide (Al₂O₃) and may block or reducepermeation of impurities, such as moisture or oxygen, to the organiclight-emitting device OLED.

The organic layers 352 r, 352 g, and 352 b may include organic materials352 rb, 352 gb, and 352 bb and the quantum dots 352 ra, 352 ga, and 352ba that are respectively dispersed in the organic materials 352 rb, 352gb, and 352 bb. The organic layers 352 r, 352 g, and 352 b may be usedtogether with the inorganic layers 351 and 353 to improve sealingcharacteristics of the encapsulating structure 350 and to planarizerough surfaces therebelow. The organic materials 352 rb, 352 gb, and 352bb may include any of various organic materials, such as epoxy-basedresins, acryl-based resins, or polyimide-based resins, and may beinkjet-printable materials.

According to an embodiment, a thickness t1 of each of the inorganiclayers 351 and 353 may be less than or equal to about 5 μm, whereas athickness t2 of each of the organic layers 352 r, 352 g, and 352 b maybe less than or equal to about 20 μm. If the thickness t1 of each of theinorganic layers 351 and 353 exceeds about 5 μm or the thickness t2 ofeach of the organic layers 352 r, 352 g, and 352 b exceeds about 20 μm,it may be difficult to reduce the thickness of the organiclight-emitting display apparatus 3 and/or to manufacture the organiclight-emitting display apparatus 3 as a flexible display apparatus.

Furthermore, the thickness t1 of each of the inorganic layers 351 and353 may be greater than about 300 nm, whereas the thickness t2 of eachof the organic layers 352 r, 352 g, and 352 b may be greater than about1 μm. If the thickness t1 of each of the inorganic layers 351 and 353 isless than or equal to about 300 nm, it may be difficult to blockpermeation of moisture or oxygen to the organic light-emitting deviceOLED. If the thickness t2 of each of the organic layers 352 r, 352 g,and 352 b is less than or equal to about 1 μm, it may be difficult touniformly disperse the quantum dots 352 ra, 352 ga, and 352 ba havingsizes from several nm to hundreds of nm.

The organic layers 352 r, 352 g, and 352 b including the quantum dots352 ra, 352 ga, and 352 ba may be inside the openings 360 hr, 360 hg,and 360 hb included in the pixel-defining layer 360. In other words, theorganic layers 352 r, 352 g, and 352 b may be in an area defined by thepixel-defining layer 360.

The organic layers 352 r, 352 g, and 352 b may include a first organiclayer 352 r that is disposed inside the first opening 360 hr andincludes first quantum dots 352 ra, a second organic layer 352 g that isdisposed inside the second opening 360 hg and includes second quantumdots 352 ga, and a third organic layer 352 b that is disposed inside thethird opening 360 hb and includes third quantum dots 352 ba. The firstorganic layer 352 r, the second organic layer 352 g, and the thirdorganic layer 352 b may be separated from each other by thepixel-defining layer 360. The first quantum dots 352 ra, the secondquantum dots 352 ga, and the third quantum dots 352 ba may be disposedon a path in which light is transmitted through the counter electrode340.

The first quantum dots 352 ra, the second quantum dots 352 ga, and thethird quantum dots 352 ba may be red quantum dots, green quantum dots,and blue quantum dots, respectively. The red quantum dots, the greenquantum dots, and the blue quantum dots refer to quantum dots thatabsorb light of a certain wavelength and emit light of a wavelengthcorresponding to red, light of a wavelength corresponding to green, andlight of a wavelength corresponding to blue, respectively.

According to an embodiment, the first intermediate layer 330 r, thesecond intermediate layer 330 g, and the third intermediate layer 330 bmay respectively emit red light, green light, and blue light having acertain FWHM, where the first quantum dots 352 ra, the second quantumdots 352 ga, and the third quantum dots 352 ba may at least partiallyabsorb the red light, the green light, and the blue light respectivelyemitted by the first intermediate layer 330 r, the second intermediatelayer 330 g, and the third intermediate layer 330 b and emit red light,green light, and blue light having a relatively small FWHM.

In other words, a FWHM of light transmitted through the first organiclayer 352 r, the second organic layer 352 g, and the third organic layer352 b may be less than a FWHM of light emitted by the first intermediatelayer 330 r, the second intermediate layer 330 g, and the thirdintermediate layer 330 b. Accordingly, color purity of the organiclight-emitting display apparatus 3 may be enhanced.

According to another embodiment, the first intermediate layer 330 r, thesecond intermediate layer 330 g, and the third intermediate layer 330 bmay emit white light, and the first quantum dots 352 ra, the secondquantum dots 352 ga, and the third quantum dots 352 ba may at leastpartially absorb the white light emitted by the first intermediate layer330 r, the second intermediate layer 330 g, and the third intermediatelayer 330 b and emit red light, green light, and blue light having asmall FWHM.

The organic layers 352 r, 352 g, and 352 b may be only in areascorresponding to the openings 360 hr, 360 hg, and 360 hb between thefirst inorganic layer 351 and the second inorganic layer 353. Therefore,the second inorganic layer 353 may include a first area 353 a thatdirectly contacts the first inorganic layer 351 and a second area 353 bthat is disposed or spaced apart from the first inorganic layer 351 bythe organic layers 352 r, 352 g, and 352 b.

The first area 353 a may correspond to an area in which thepixel-defining layer 360 is disposed, whereas the second area 353 b maycorrespond to areas above the pixel electrodes 320 r, 320 g, and 320 brespectively exposed by the openings 360 hr, 360 hg, and 360 hb includedin the pixel-defining layer 360.

According to embodiments of the inventive concept, by disposing anencapsulating structure including an organic layer having dispersedtherein quantum dots, an organic light-emitting display apparatus withenhanced color purity that may be easily manufactured as a flexibledisplay apparatus, and a method of manufacturing the same may beprovided.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. A display apparatus comprising: a substrate; apixel electrode over the substrate; a pixel-defining layer comprising anopening that exposes at least a portion of the pixel electrode; anintermediate layer, which is over the portion of the pixel electrodeexposed by the opening and comprises an organic emission layer; acounter electrode over the intermediate layer; and an encapsulatingstructure, which is over the counter electrode and comprises at leastone inorganic layer and at least one organic layer, wherein the at leastone inorganic layer comprises a first inorganic layer and a secondinorganic layer over the first inorganic layer, the first inorganiclayer being in the opening and extending outside the opening, whereinthe at least one organic layer comprises quantum dots and comprises alower organic layer and an upper organic layer over the lower organiclayer, the lower organic layer being arranged between the firstinorganic layer and the second inorganic layer, the lower organic layerbeing in the opening, and wherein a thickness of the encapsulatingstructure in the opening is greater than a thickness of theencapsulating structure outside the opening.
 2. The display apparatus ofclaim 1, wherein the thickness of the at least one organic layercomprising the quantum dots is less than or equal to about 20 μm.
 3. Thedisplay apparatus of claim 1, wherein the at least one inorganic layerhas a thickness less than or equal to about 5 μm and comprises at leastone of silicon nitride (SiN_(x)), silicon oxide (SiO₂), siliconoxynitride (SiO_(x)N_(y)) or aluminum oxide (Al₂O₃).
 4. The displayapparatus of claim 1, wherein the pixel electrode comprises a reflectiveelectrode that reflects light, and the counter electrode comprises atransparent or semi-transparent electrode that at least partiallytransmits light therethrough.
 5. The display apparatus of claim 1,wherein the organic emission layer emits blue light.
 6. The displayapparatus of claim 5, wherein the quantum dots absorb at least a part ofthe blue light and emit yellow light, and at least a part of the bluelight is transmitted through the at least one organic layer comprisingthe quantum dots.
 7. The display apparatus of claim 1, wherein thesecond inorganic layer comprises a first area directly contacting thefirst inorganic layer, and a second area that is spaced apart from thefirst inorganic layer by the lower organic layer.
 8. The displayapparatus of claim 1, wherein the at least one inorganic layer furthercomprises a third inorganic layer over the upper organic layer.
 9. Thedisplay apparatus of claim 1, wherein the pixel electrode comprises afirst pixel electrode, a second pixel electrode, and a third pixelelectrode that are apart from one another, the pixel-defining layercomprises a first opening, a second opening, and a third opening thatexpose at least portions of the first pixel electrode, the second pixelelectrode, and the third pixel electrode, respectively, and theintermediate layer comprises a first intermediate layer over the firstpixel electrode, a second intermediate layer over the second pixelelectrode, and a third intermediate layer over the third pixelelectrode.
 10. The display apparatus of claim 9, wherein the at leastone organic layer comprising the quantum dots comprises a first organiclayer that is in the first opening and comprises first quantum dots ofthe quantum dots, a second organic layer that is in the second openingand comprises second quantum dots of the quantum dots, and a thirdorganic layer that is in the third opening and comprises third quantumdots of the quantum dots.
 11. The display apparatus of claim 10, whereinthe first intermediate layer, the second intermediate layer, and thethird intermediate layer emit red light, green light, and blue light,respectively, and the first quantum dots, the second quantum dots, andthe third quantum dots are red quantum dots, green quantum dots, andblue quantum dots, respectively.
 12. The display apparatus of claim 10,wherein all of the first intermediate layer, the second intermediatelayer, and the third intermediate layer emit white light, and the firstquantum dots, the second quantum dots, and the third quantum dots arered quantum dots, green quantum dots, and blue quantum dots,respectively.
 13. The display apparatus of claim 10, wherein the firstorganic layer, the second organic layer, and the third organic layer areseparated from one another by the pixel-defining layer.
 14. A method ofmanufacturing a display apparatus, the method comprising: forming apixel electrode over a substrate; forming a pixel-defining layer overthe pixel electrode, the pixel-defining layer comprising an opening thatexposes at least a portion of the pixel electrode; forming anintermediate layer over the portion of the pixel electrode exposed bythe opening, the intermediate layer comprising an organic emissionlayer; forming a counter electrode over the intermediate layer; andforming an encapsulating structure over the counter electrode, theencapsulating structure comprising at least one inorganic layer and atleast one organic layer, wherein the at least one inorganic layercomprises a first inorganic layer and a second inorganic layer over thefirst inorganic layer, the first inorganic layer being in the openingand extending outside the opening, and wherein the at least one organiclayer comprises quantum dots and comprises a lower organic layer and anupper organic layer over the lower organic layer, the lower organiclayer being arranged between the first inorganic layer and the secondinorganic layer, the lower organic layer being in the opening such thata thickness of the encapsulating structure in the opening is greaterthan a thickness of the encapsulating structure outside the opening. 15.The method of claim 14, wherein the thickness of the at least oneorganic layer comprising the quantum dots is less than or equal to about20 μm.
 16. The method of claim 14, wherein the at least one inorganiclayer has a thickness less than or equal to about 5 μm and comprises atleast one of silicon nitride (SiN_(x)), silicon oxide (SiO₂), siliconoxynitride (SiO_(x)N_(y)), and aluminum oxide (Al₂O₃).
 17. The method ofclaim 14, wherein the forming of the encapsulating structure furthercomprises: forming a third inorganic layer of the at least one inorganiclayer over the upper organic layer.
 18. The method of claim 17, whereinthe forming of the organic layer comprises: forming an organic materialhaving dispersed therein the quantum dots in the opening included in thepixel-defining layer via inkjet-printing; and curing the organicmaterial having dispersed therein the quantum dots.
 19. The method ofclaim 14, wherein the forming of the second inorganic layer comprisesforming the second inorganic layer to comprise a first area directlycontacting the first inorganic layer, and a second area that is spacedapart from the first inorganic layer by the organic layer including thequantum dots.